So I have been doing a lot of ActionScript lately and I should say that is nice to have to use the Flash IDE only 10% of the time, and I am looking for ways to reduce that from 5% to 0% of the time, it is tricky since at work I have to use a MAC and at home I have to use a PC, but I believe I have found the best of both worlds.
In one hand we have TextMate for the MAC
I must say that it is a great editor and not only that but it allows you to tie in MTASC to compile your movies, add a little bit more of majic and you have an almost 100% Development tool where you only need to use the Flash IDE as a Guide or to build your library.
Another nice thing about this editor is that there are a lot of plugins out there as well as Bundles for you to do all the work straight into Textmate. Of course this is not recommended for everyone and not for every single case but it is nice to know that there is the ability to do it this way.
Another thing you want to check out is SWFMill, now if you tie TextMate, MTASC, SWFMill and a good tracer you are all set.. or should I say I am all set? ;) because I am working on it.